Gravity Falls' Darkest Mystery
by Art n' Music
Summary: After a traumatic event, Dipper and Mabel are moved to the care of Grunkle Stan, who seems to have gotten weirder. Not only him, Gravity Falls has also darkened. Dipper must put the puzzle pieces together and travel to the darkest regions to discover the book's deepest secret and solve Gravity Falls' darkest mystery. DPxCC MPxOC
1. Chapter 1

**Chapter 1: Great Changes**

On the road, an automobile drives along the clear road in the middle of nowhere. Inside the car, a detective called Dipper and his twin sister, all-cheery Mabel, wait patiently as their parents take them to someplace 'exciting', as they put it. The twins have same slightly curled brown hair, except Mabel's hair reaches to her lower back and Dipper always wears a blue forest hat on top of his messy hair. He usually wears a red shirt with a blue vest and cargo shorts and sneakers. His sister wears a variety of stylish sweaters, a headband of the same color, and always wears a skirt and black Mary-Jane shoes.

Right now, Mabel listens to too-optimistic songs and watches the scenery while Dipper reads the book he found in Gravity Falls a few years ago. A leather book full of legendary creatures told as myths. He reads a passage about mysterious shadows appearing everywhere when his sister asks, "Are you going to tell us where we're going now?"

"Mabel, if we told you, then a surprise will lose all meaning." their father says.

"I bet it's the zoo." She turns and finds her brother reading again. "Will you ever put that book down, Dipping Sauce? You've probably read it a million times in three years."

"I know, but it's really fascinating that all the things people think are legends are actually real. We've seen a lot of strange happenings at Gravity Falls three years ago, but there are still lots more to find out. I'm also wondering why the author just mysteriously stopped. And who is the person the author calls 'He'? These things have been rattling in my head for I don't know how long."

"Well on this trip, just forget about the book and 'He' and mysteries. This is the time to have fun. Maybe finally get a girlfriend."

"Mabel! I'm able to get a girlfriend. I just haven't found one that…clicks with me. You know what I mean?"

"Maybe you haven't found the right girl because you haven't hung out with one. All you do is turn them down when they ask you on a date."

"That's because they weren't the right one."

"So who is the right one? A vampire?" Mabel kids.

"My life is not like those Twilight nonsense."

"Hey! The Twilight Saga is not nonsense! Vampires are real!"

"I'm not saying they're not real." Dipper quickly says. "I'm just saying that life isn't full of romantic mythical creatures finding a soul mate for all eternity."

"That will happen."

The male twin pats Mabel's back, saying, "Keep that in mind. So how long till we get to wherever we're going?"

"Should be another hour." the mother answers.

The father asks, "You know what I just found out? The radio's not on." He presses a button and the radio starts playing Party Rock Anthem by LMFAO. Everyone begins dancing to the beat, except Dipper who suddenly got a chill. He looks ahead and finds a bridge coming closer and a truck with its cargo shaking slightly. "Uh guys, you should pay more attention to the road."

The parents turn up the volume and don't hear him. Mabel starts singing to the song and soon the others sing with her. When they drive closer, the detective can see large logs shaking more briskly as the straps become loose. "I-I'm serious. I feel like something gonna happen."

Again, they don't hear him. Now the logs are really shaking. Fear starts growing in Dipper as they drive closer. When the car is close to the bridge, the straps on the bed of the truck suddenly snaps and the logs start rolling off. As some of the logs roll to the fence, the twin yells, "Mom, dad, look out!"

The two finally look out and everything seems to flash altogether. Next thing the twins know, the front half of the car has vanished under a few logs, and their parents. Mabel and Dipper stare ahead with unbelief, not registering what happened. Hours or minutes later, Dipper broke the silence, "W-w-what…"

Tears build up in Mabel's and she starts whimpering. Her twin snaps out of his reverie and jumps out of the wreckage and starts pacing worriedly while muttering nonstop. He keeps looking at the road for any passersby, but the road remains empty for a while. "Oh man. How are we supposed to get back? Ugh, stupid of me to leave my phone at home." The boy turns back to his sister and sees her breaking down hard. He walks up and says, "Mabel, it's alright. Everything's gonna be okay. Just wait."

She continues to cry, making Dipper sigh in defeat, and he takes out her phone. The boy dials the emergency numbers and soon he starts telling the emergency man what happened. "We're somewhere on Chester Street. I don't know where, our parents were taking us to someplace as a surprise. Okay, but hurry. I don't think my sister can last any longer." Dipper hangs up the phone and walks back to his distraught sister. He sits next to her and starts patting her back, feeling the depression finally taking over his mind.

* * *

**I know its short, but I just don't want to give too much away, and this seemed like a good way to end this chapt, in a way. It'll get better in the next chapters. **


	2. Chapter 2

**Chapter 2: One Year Later**

In the forest of Gravity Falls, Oregon, Stan Pines leads a group of tourists through his home he calls the Mystery Shack, the tourist trap. "And right here is a fin-print of the Legendary Gobblewonker."

Everyone 'ooh's' at the rock and some snap photos. Soon, the tourists stroll through the gift shop for souvenirs and exit the Mystery Shack. Stan closes and locks the door, saying, "Another great day of ripping people of their money. Is there anything sweeter, Soos?"

Soos, a portly man with a small head and wearing a gray hat, forest green shirt with a question mark, and gray shorts and shoes, says, "Actually, I can think of other sweeter things. Candy, for instance. And strawberries, sugar, sweetener…"

"You know what I mean." He takes off his dark suit and continues, "I'm going to watch some TV, Soos. Make sure you keep an eye on the doors and windows. We don't want any _unwanted visitors_ breaking in."

The employee pales a little and pulls out a two-barrel shotgun. "Don't worry. I'm prepared."

"Good." The great uncle was about to walk into the employees-only room, also known as the living room and stairs to the attic, when the doorbell rings. "Oh, who could that be? Don't they see the closed sign on the door? Unless…" Fearing the worst, he grabs a pistol from nearby and slowly walks to the locked door, survival instinct kicking in. He peeks into the peephole and finds a human face. "Huh?" Stan opens the door and gets a better look at two teens with suitcases. One is lightly tan, light-built, and wearing a blue forest hat, blue vest with a large question mark stretching across the entire left half, a dark red shirt with an all-seeing eye, and cargo shorts with large pockets and hiking boots. Next to him is a pale teen that looks Goth with the black skull shirt, elbow-length and fingerless gloves colored black, a gray skirt with black squares in a checkered pattern, with jeans underneath that turn to a darker gray as it goes down, and knee-high boots full of silver buckles. She also wears a space-black belt that sags with a chain, a silver necklace, skull ring, and her shoulder-length spiky hair and nails are space-black. "Can I help you two?" the tour guide asks, slightly annoyed.

"Long time no see, Grunkle Stan," The boy states.

"Grunkle? Nobody calls me that except a couple kids named Dipper and Mabel-Waaaaiiiittt…" He gets a better look at the twins and sees the familiar determination in the boy's eyes. "Dipper! Well, isn't this a surprise! Puberty really did great on you. And…Mabel?" he asks, referring to the Goth. She simply looks down sullenly and walks in the house, ignoring Soos who is giving her a weird look. Stan turns back to his great nephew and asks, "Is that really…?"

"Yep," Dipper answers sadly, also walking in the shack. "That's Mabel."

"What happened?"

"It's kinda a long story."

Stan locks the door again while saying, "We've got plenty of time as of right now."

"Well, did you hear about the car incident a year ago?"

The great uncle says, "Not one I'm familiar with, kid."

"Well, uh…Our parents got in a car accident which ended up making me and Mabel become orphans.

"Are you serious?"

"Yes. And as you can see, Mabel's not handling it great."

Stan looks back at the Goth twin and a new feeling grows inside his heart that he's not familiar with. "Wow. I mean…But why are you two here?"

"Well first, we lived with our grandparents back in Washington. There, Mabel just stayed in her room for about two months, crying her eyes out. Whenever she left her room, she doesn't talk, doesn't play, she doesn't even smile. Then she turned to…well that halfway through the school year." The boy gestures to the Emo Mabel.

"Okay. But why are you two here now?" the grunkle asks again.

The detective turns to his sister, who's gloomily looking out the window. He then takes out two vanilla envelopes out of his pack and hands them to Grunkle Stan. "They didn't want Mabel to hear this, but Grandma and Grandpa Fores won't be around any longer. They knew that this would only make Mabel even more in despair and in that state…"

"Okay, I get it kid. So what did they tell her instead?"

"They just said that you'll have a better life at our great uncle's place. They're place wasn't made to have teens live in."

"Alright then, you and Mabel can have the attic like before. It hasn't really changed much since you guys left."

"Thanks Grunkle Stan. C'mon Mabel." He grabs his bags while Mabel lugs hers up the stairs. Stan opens the envelopes and finds two papers. "Birth Certificates? I guess you two really are staying." He sets them down and grabs his stack of cash.

Dipper heads back and asks, "By the way, how's Gravity Falls?"

Stan stops his money counting and answers, "Unlike your room, it's changed."

"Really?" After thinking for a short time, he follows his sister up and the old man looks out the window in time to see a spot of blackness flash in the woods. "It's changed greatly."

In the attic, Dipper unpacks his bags and either puts them in the closet or under the old but familiar bed on the left side of the diamond window. He looks over to Mabel, whose just staring out the window again, her bags left untouched. "You gonna unpack Mabel?" he asks.

She ignores him with her usual silence, which makes Dipper sigh. "Fine. I'm going into town. You should come too."

The Emo shakes her head.

"Mabel, you can't live the rest of your life isolated. I know the incident really brought you down, but that's life. Stuff happens. It'll only get better if you keep on going."

The female twin turns her head and gives Dipper a look. By now, the detective learned how to read facial expression from her gloomy sister, so he says, "Fine. Stay here and rot but I'm checking the town. I'll see you at dinner."

He walks downstairs and passes through the TV room where Grunkle Stan sits. "Where're you off to?"

"To check out town and see how much it 'changed'," he answers with air quotes.

"Alright but word to the wise, be wary of the forest. And here." The old man tosses Dipper an AMT Auto-mag III and asks, "You know how to work a gun?"

"Yeah. But why?" he asks, looking at the gun cautiously.

"Like I said. Gravity Falls' changed."

"Uh…alright. Sir Creepy." he whispers the last few words. The detective unlocks the wooden door and walks out to the familiar outdoor yard. He scans the dense woods and smiles, a few memories reappearing in his head. Suddenly, a shadow appears and vanishes in the forest in less than a second. Dipper blinks and wonders if he saw what he saw. He walks closer to the forest and scans inside but doesn't see anything out of the ordinary, which is even weirder in this town.

He pushes the weird occurrence away, making a mental note to look up shadows in the 3 book, and walks to the town while putting the gun in his pocket.

Once the detective arrives at the town of Gravity Falls, he finds that it hasn't changed much. Or not at all. He recognizes the policemen, Sheriff Blubs and Deputy Durland, walking out of the donut shop. They seem to have grown some gray hair over the past few years. Some other people he knows is the pizza man, the journalist Toby Determined, Lazy Susan walking out of a cat store with cat food and litter in hand, and a tall lumberjack with red hair, beard, chest hair, and arm hair named Manly Dan. He also spots Old Man Mcgucket sleeping in the junkyard. So far, nothing looks different, except that everyone has a pistol on their person, even the kids. "What was Grunkle Stan talking about when he said this place changed? Besides the weaponry, I don't see anything different." he thinks aloud.

"Do my eyes deceive me? Is that really you, Dipper?" a voice asks behind him.

Dipper recognizes the voice, though it's slightly deeper than he remembers, and he turns around to find a short man wearing a blue tuxedo and blonde hair bigger than his chubby head, and has a silver gun holster on his side. The detective says, "Well well well. If it isn't Lil' Gideon. Though, not so little anymore."

"It is you! Well, my word, how you've grown. How've you been?" Gideon asks.

"It was actually great, considering I didn't have to worry about you for four whole years."

"Same here. So if you're here, then that means that Mabel is here, right?"

"Well, yeah, she's here as well. But she doesn't want to meet you." He whispers the last part, "Or anyone, for that matter."

"Oh, don't worry. I'm not googling over her anymore. In fact, I have a girlfriend now."

"You?" Dipper asks surprisingly. "Who is dumb enough to actually date you?"

"Sweetie! I'm back!"

The male twin turns his head and finds a blonde-haired girl wearing a strapless sky-blue shirt that shows her midriff, small white shorts with a gray belt loosely wrapped, and high-heel boots that reach to her knees and has about a ton of make-up on her face and large hoop earrings. She stops next to Gideon and asks after giving him a peck on the cheek, "Did you miss me, honey?"

"I sure did, my little flower angel."

Pacifica Northwest turns to Dipper and widens her eyes. "Dipper? Is that really you?"

"The one and only, _Pacifica_," he says cheerfully but with venom.

"You sure? I don't remember the geeky Dipper being a hunk." She then realizes what she just said. "Whoa, didn't think 'Dipper' and 'Hunk' will be in the same sentence."

The detective looks around before saying, "You know, I think you two make the perfect match."

"Really?" the popular girl asks dully.

"Yeah. Two arrogant, selfish, spoiled, rich jerks smooching while others serve you for lower than minimum wage."

"Why you lil'-!" the small man shouts while starting to walk to the twin with fists but his girlfriend stops him. She walks up to Dipper with a serious face, revealing that she and Dipper are the same height. "Listen, Pines. You do not want to insult me or Gideon. Especially me," she says maliciously.

"Why shouldn't I?" he asks, not fazed by her menacing eyes.

"I learned some things since the last time we met and I'm not afraid to use them on you."

"I'm not afraid of you, Pacifica. And as it so happens, I learned some things, too."

"Oh, really?" She takes a few steps back and reaches behind her. "Why don't I show you a demonstration?" the popular girl continues to search for something in her back pocket but comes out empty-handed. Dipper clears his throat to get her attention and shows her a bejeweled gun he's twirling around his finger. "Looking for something?"

Pacifica growls and orders, "Gideon, give me yours!"

"With pleasure." The short man reaches for his gun in the holster but finds it missing. "Huh?" He looks at the detective who's holding another gun in his hand. "You missing something, too?"

"But how did you…?"

"I told you, I learned a few things," he says, smirking.

Snarling, the girl rolls up her invisible sleeves when Gideon stops her this time. "My sweet, how 'bout I try?"

"Oh-ho. You're going to fight me, chubby?" Dipper mocks.

"Why, of course. I actually have a score to settle with you," he says sarcastically cheery.

The detective gets into a fighting position and taunts the man with his hand. "Bring it."

The chubby man swings a fist at him but the male twin just catches it in his hand and twists it around onto his back. He kicks the small man, making Gideon stumble around before retaliating with punches one after the other, but Dipper dodges or halts the rampage expertly without tiring. After a while, Gideon stops and breathes hard, staring at his enemy angrily. "What? You too scared to fight back?"

"Of course not. You just don't pose a threat to me in any way, so what's the point?"

"Oh, I see now. The so-called detective Dipper Pines is too afraid to fight!" he shouts, alerting a few bystanders in the vicinity.

"Excuse me?" the twin asks.

"You said that you fought ghosts, gnomes, even a bear with multiple heads yet you don't want to battle me, Gideon. I bet you're nothing but a big chicken!"

"Okay man, you are coming really close to crossing my line." Even more people stop and gather around the skirmish.

"I noticed you don't have a girlfriend, Dipper. Why is that? Oh, you probably don't have one because they run away in disgust."

"I suggest you shut up, Gideon," the detective growls, steam coming out of his ears if it was a cartoon.

"You know, I think your sister didn't come with you because she's too embarrassed to have you as a brother. It must have killed her having to live with you."

"That's it!" Dipper tackles the fake psychic and repeatedly punches him in the face. Gideon struggles to get the enraged man off of him then kicks him off in the stomach. He ignores it and kicks Gideon into the wall. The detective takes out his gun in his back pocket and aims it at the dazed man, making everyone gasps and Gideon stares at the weapon fearfully. When Dipper pulls the trigger, a loud bang echoes everywhere and the crowd stares at the victim. Gideon, his eyes closed, slowly opens them and finds himself alive, a bullet-hole on the wall next to his head. The detective grabs his annoyance's collar again and lifts him up to eye-level. "That was a warning shot, you fake. The next time you step out of line, you'll have a matching pair on your forehead," he warns, lifting the gun close to his face.

"I-I don't remember you being this violent, Dipper," Gideon pants.

"You have no idea what I've been through, Gideon." He throws him toward his girlfriend and finishes while tossing them their guns, "And you never will."

After Pacifica helps her boyfriend up, they quickly leave the fight area and slightly shaken crowd slowly disperses. Dipper crosses his arms and was about to walk when someone says, "Nice job beating that kid up."

He turns around and sees a man wearing a black jacket with a stitched red heart and a gray shirt underneath, tight jeans, and shaggy black hair and the other a red-haired woman wearing a red shirt and green checkered jacket and blue shorts and boots. Dipper recognizes them and guesses, "Wendy? Robbie?"

"Hey there, Dipper. Long time no see," Wendy greets. The two high-five each other and Wendy asks, "So Dipper, how was your life away from Gravity Falls?"

"Quite boring, actually. A part of me is glad that I'm back."

"Well, why don't I get you an ice cream cone as a welcome back gift?" She walks to the ice cream parlor and the twin turns to Robbie, raising a hand. "No hard feelings, right Robbie?"

He narrows his eyes and says, "Maybe. You're not going to try and hit on my girl, are you? Because I should let you know, we're-"

"Married?" the detective finishes.

The husband widens his eyes and asks, "How'd you know?"

"I saw the ring on both of your fingers. And you don't have to worry. I've grown out of that crazy phase."

"Really?"

Dipper nods his head.

"Oh. Alright." Robbie smiles and asks, "So, what brings you back to Gravity Falls?"

"Oh, you know. Family matters. Nothing big," he answers, looking away. "So far, nothing's changed here."

The temporarily blissful smile falls from Robbie's face and he looks around before saying, "That's where you're wrong."

"What? What do you mean?"

"Kid, there's a reason everyone is carrying a gun. Even the children. Something evil has appeared and is terrorizing everyone."

"Really? What do they look like?"

"They look like shadow beings. Like just pure shadow. No detail on them except for white orbs that always looks hungry. It's like someone made a black paper cutout of a person and glued white circles on the heads."

_Shadow beings? Why does that sound familiar?_

"I'm back!"

The two turn around and Wendy walks up, carrying three ice cream cones with different flavors in each one. She hands one to Dipper and the other to Robbie, asking, "So what were you two doing while I was gone?"

"Oh, not much. I was just telling Dipper here about Gravity Falls," the husband says while locking the detective in a head-lock and giving him a noogie.

She chuckles and says, "Well alright. It was nice seeing you again Dipper but we have to get going. See ya later." The couple walks away and Dipper shouts, "See ya!" When they disappear, Dipper's grin disappears when his thoughts return to what Robbie said. While rubbing his chin, he mutters, "Shadow beings, huh? Where have I heard that before?" He remembers the small flash of black in the forest, and reviews all the things he knows when the book comes to mind. "Wait a minute, I think I read about them before." The detective starts reaching for the old leather book etched with gold when he glimpses something behind him with his detective-enhanced sight. But when he turns around, sliding the book back in his vest, there's nothing but a dark alleyway with some garbage in, and the forest at the other end. He stares at the place in question for a while before shrugging it off and finally opening the mysterious 3 book. He flips the pages full of myths and legends until he finds two whole pages with black drawings of humanoid wisps. "Ah ha! I knew I've heard of them before. Alright then, let's see…" Before he can read the passages, someone with an accent behind him says, "Hi there."

With a skill he quickly mastered, Dipper closes the book and stuffs it back in his vest in one fluid motion before turning around. Standing in front of him, about half-a-head smaller than him, is a girl that looks Korean with long, black hair, peach skin, and deep blue eyes behind round glasses. The girl wears a jade green baggy shirt with the sleeves slightly covering her hands, a really dark blue skirt, and black sandals with dark green socks. In the back of his mind, the detective thinks she looks familiar. "Hi. Um, is there something you need?"

She nervously rubs her arm and says, "I just wanted to say welcome back. Candy?" she takes out a mint from her pocket and hands it to the detective, and that's when the twin remembers the girl. "Candy! I thought you looked familiar."

"Oh. You remember me," she chuckles, averting her eyes. Dipper thought he saw her blush a little.

"How can I forget? You came to the Mystery Shack almost every day for a sleepover."

Candy chuckles again, placing her hands behind her back, then asks, "So, where's Mabel? It would be nice to see her again."

His smile turns to a frown and looks away before starting to walk away, followed by a confused Candy. "She's here, but she's not the same Mabel you know."

"Why?"

"Well, something horrible happened to us and it led Mabel to become an Emo."

"Emo?"

He nods his head, continuing looking down on the sidewalk.

"But, Mabel would never become an Emo. In one of our games, it said that she would become one and Mabel promised she'd never in a bajillion years," the Korean girl reasons, still not believing the fact.

"What game?" he asks, his detective instincts kicking in. He pushes the feeling aside and continues, "Never mind. But there are no promises in what your life will bring. Sure, you say that you'll never become what you don't want to be but you never know what your future is."

Candy sees that the depression isn't going to leave soon on its own so she looks around to find something to cheer the twin up. She checks the time on her watch, which is hidden in her sleeve, and looks at the diner. She smiles and grabs her friend's brother's hand, pulling him toward the building. "Maybe all you need is some nutrition for your brain."

"I don't think so," the detective argues but lets her drag him.

"I think so. You need something to distract you right now. Besides, they're having a couple's special right now."

"What?"

"They're having a two-for-one special!" Candy quickly shouts, putting her hands behind her back and nervously looking around. Dipper stares at her confusedly, noticing the slight pink tint reappearing on her pale cheeks and her tense eyes. "Maybe we both need some food," he suggests.

She timidly chuckles, "Y-yeah. Good idea."

* * *

Deep in the forest, a black wisp shoots through the many trees. It heads into a part of the woods that always remains dark and enters a large, ominous mansion about three stories high with an attic. The shadow zips through the creaky door hanging on one hinge and stops in one room that's entirely black with shadow. He stops and looks up at the darkness with hungry circles for eyes. "Master," it hisses with a voice like the wind.

A white line appears feet above the shadowy floor and splits open, revealing a white and black eye. The eye looks down at the wisp and the shadow says, "The boy and girl you spoke of. They have returned."

"Oh boy! Looks like everything is going smoothly!" the eye says in a merry voice. "Now that the pine tree and shooting star are here, it's only a matter of time before I get my revenge. After all, revenge tastes so sweet." It starts laughing while the eye closes and vanishes.

**WKH ZKHHO PHDQV PRUH**


End file.
